Advanced T‐In ₂ Se ₃ /M‐WS ₂ /B‐WSe ₂ Photodetectors Enabled by Cascaded Band Tailoring and Charge Reservoir Engineering

Abstract Taking advantage of their unparalleled electrostatic and optoelectronic properties, 2D layered materials (2DLMs) have emerged as alluring building blocks for crafting advanced photodetectors. Nevertheless, preceding research has predominantly concentrated on rudimentary designs incorporating single‐channel or single‐junction setups, failing to exert the full potency of 2DLMs. Therefore, there is still an imperative requirement to develop innovative device architectures grounded in novel physical mechanisms. Herein, a T‐In ₂ Se ₃ /M‐WS ₂ /B‐WSe ₂ heterojunction photodetector boasting pronounced gate‐tunability is devised, achieving remarkable light on/off ratio of 5.8 × 10 ⁴ and detectivity of 1.1 × 10 ¹³ Jones at V _gs = −25 V, alongside competitive responsivity and gain of 633 A W ⁻¹ and 1943 at V _gs = 30 V. Energy band analysis has determined that the former is associated with the synergy of the cascaded band alignment and the high degree of depletion effect, while the latter is ascribed to the intermediate electron reservoir enabling high‐efficiency spacial separation of photoexcited electron−hole pairs. Leveraging this device as the pivotal sensing component, proof‐of‐concept applications spanning broadband optoelectronic imaging and automatic driving are demonstrated. This study presents a novel paradigm for constructing 2DLM‐based photodetectors with outstanding comprehensive performance, thereby establishing a fascinating platform capable of catering to the diverse demands of next‐generation optoelectronic industry.